Answer:
4.30 × 10²⁰ atoms
Explanation:
You need to find out how many moles you have. First, convert milligrams to grams.
62.5 mg × (1 g)/(1000 mg) = 0.0625 g
Next, use the molar mass to convert from grams to moles.
0.0625 g ÷ 87.62 g/mol = 7.13 × 10⁻⁴ mol
To convert from moles to atoms, you need to use Avogadro's number (6.022 × 10²³). Avogadro's number is the number of atoms in a mole.
7.13 × 10⁻⁴ mol × 6.022 × 10²³ atoms/mol = 4.296 × 10²⁰ ≈ 4.30 × 10²⁰ atoms
You will have 4.30 × 10²⁰ atoms of strontium.
The number of Strontium atoms are 4.30 × 10²⁰ atoms
Given:
Mass of Strontium = 62.5 mg × (1 g)/(1000 mg) = 0.0625 g
Molar mass of Strontium = 87.62 g/mol
To find:
Moles of Strontium = ?
Number of moles:It is defined as given mass over molar mass.
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}\\\\\text{Number of moles}=\frac{0.0625 g}{87.62 g/mol }\\\\\text{Number of moles}=7.13 * 10^{-4} mol[/tex]
Avogadro's number is the number of atoms in a mole (6.022 * 10²³)
Conversion of moles into atoms:
[tex]7.13 × 10^{-4} mol * 6.022 * 10^{23} atoms/mol \\\\\text{ Sr atoms}= 4.296 * 10^{20} = 4.30 * 10^{20} atoms[/tex]
Thus, Strontium atoms will be 4.30 × 10²⁰ atoms.
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In science class, Jake mixed water with differing amounts of an unknown liquid. After mixing the liquids, he heated 20 milliliters (ml) of each mixture and observed how quickly it boiled. The table shows his results.
According to the question, each mixture decrease the boiling point of the water.
What is boiling point ?Boiling temperature is defined as the temperature at which liquid change into a vapour at the atmospheric pressure at sea or ocean level.
For example the boiling temperature of water is 100 degree celcius.
Thus, each mixture decrease the boiling point of the water, option "A" is correct.
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Give two examples of neutralization
Answer:examples for neutralization - treating indigestion,treatment for insect bites.hope it help you
Explanation:
Mike wants to galvanize iron to protect it from rusting. Which metal should he use?
A
platinum
B.
aluminum
C.
copper
D.
zinc
E.
tungsten
Answer:
D. Zinc.
Explanation:
Galvanization is a metal-coating process which involves the application of a thin layer of zinc to an iron or steel, so as to prevent rusting or corrosion.
The zinc metal protects the iron from rusting by sealing the surface of the iron and thus, preventing weathering and oxidation.
Hence, if Mike wants to galvanize iron to protect it from rusting. The metal he should use is zinc (Zn) because a coating of zinc would protect the iron (Fe) by corroding first when exposed to moisture or the atmosphere.
Answer:
b
Explanation:
How do weathering and deposition differ? Weathering breaks down rocks; deposition leaves them in new places. Weathering has to do with air; deposition has to do with plants. Weathering occurs only in summer; deposition occurs year-round. Weathering can be chemical or physical; deposition is only chemical
Answer:
A. Weathering breaks down rocks; Deposition leaves them in new places.
Explanation:
Weathering is basically the complete process of rocks breaking apart. In contrast, deposition is when the rocks are moved and carried away from their original place and put in new locations.
Answer:
a
Explanation:
how scientific inferences can be made from scientific observations
Answer:
The scientific method is applied to inference through the steps taken to make both inductive and deductive inferences. Inductive inference begins with an observation, and then a pattern of such observation develops. One then makes a hypothesis based on the pattern and finally a theory based on the hypothesis
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Iron and aluminum are examples of
Answer:
Iron and aluminum are both examples of metals that are used commonly in everyday life.
Explain why chlorine is a gas while iodine is a solid yet both are halogens. Select one: a. Both iodine and chlorine differ in strength of metallic bonds b. Chlorine has strong inter molecular forces than iodine c. Iodine molecules are large with strong inter molecular forces than chlorine
Answer:
Chlorine has strong inter molecular forces than iodine
Explanation:
Answer:
Chlorine has strong inter molecular forces than iodine
Explanation:
I2 is a solid while Cl2 is a gas because Iodine molecules are larger and therefore experience stronger intermolecular forces.
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Which scientist developed a new model of planetary motion?
Answer: Johannes Kepler
Answer:
i believe the answer us kepler
Explanation:
Di- Ethyl zinc is a chemical used in the library to protect books from worms, its composition is 53% Zinc, 38.9% Carbon, and 8.1% Hydrogen (At mass of Zn=65.4, C=12, H=1). Find the empirical formula of a compound
Answer:
ZnC4H10
Explanation:
The empirical formula of a compound refers to the formula that gives the simplest whole number ratio of each atoms of the elements in the compound.
The empirical formula is calculated thus:
The given percentages in the question represent the mass in grams of each element in the compound.
Zinc= 53%, C= 38.9%, H= 8.1% which represents 53g, 38.9g and 8.1g of each element respectively.
Molar Mass of Zn= 65.4 g/mol
Molar Mass of C= 12 g/mol
Molar Mass of H= 1 g/mol
Step 1: Divide the mass of each element by the molar mass given to convert to moles:
Zn= 53/65.4 = 0.81moles
C= 38.9/12 = 3.24moles
H= 8.1/1 = 8.1moles
Step 2: Divide each mole value by the smallest number of moles calculated, which is 0.81moles:
Zn= 0.81/0.81 = 1
C= 3.24/0.81 = 4
H= 8.1/0.81= 10
This is the mole ratio represented in the subscript of each element in the empirical formula:
That is, Zn (1) C (4) H (10)
Empirical formula= ZnC4H10
A white rhinoceros weighs about 1,500 pounds (lb). How many tons (T) does the rhinoceros weigh? (1 T =
A. 1.5 T
o
B. 1 T
C. 0.75 T
D. 0.5 T
Answer:
C
Explanation:
1 lb is 0.0005 T. So if you can do the math, (1500x.0005) it comes out to 0.75 T.
The electron in a hydrogen atom can undergo a transition from n = 4 to n = 3, emitting a photon with energy 1.06 × 10 –19J. Use this transition to answer the following questions.
i. What is the wavelength of this transition?
ii. How does this transition show that the position of the electron is quantized?
Answer:
Wavelength (λ) = 1.875 × 10⁻⁶ m
Explanation:
Given:
Energy (e) = 1.06 × 10⁻¹⁹ J
Find:
Wavelength (λ) = ?
Computation:
e = hc / λ
λ = hc / e
where c = 3 × 10⁸
Planck's constant (h) = 6.625 × 10⁻³⁴
So,
Wavelength (λ) = (6.625 × 10⁻³⁴)(3 × 10⁸) / (1.06 × 10⁻¹⁹)
1. Wavelength (λ) = 1.875 × 10⁻⁶ m
2. Given n = 4 to n = 3 both are integer not fraction so, electron is quantize
In the laboratory, a volume of 100 mL of sulfuric acid (H2SO4) is recorded. How many g are there of the liquid if its density is 1.83 g / cm3?
Answer:
[tex]\large \boxed{\text{183 g}}[/tex]
Explanation:
[tex]\begin{array}{rcl}\text{Density} & = & \dfrac{\text{Mass}}{\text{Volume}}\\\\\rho & = &\dfrac{m}{V}\\\\1.83 \text{ g$\cdot$ cm}^{-3} & = & \dfrac{m}{\text{100 cm}^{3}}\\\\m & = & \text{183 g}\\\end{array}\\\text{There are $\large \boxed{\textbf{183 g}}$ of sulfuric acid.}[/tex]
What is atom economy? A. All of these B. The system that determines how much 1 mole of a pure element costs. C. The measure of how much of the reactants end up as products in a chemical reaction. D. The system of exchanging electrons that occurs in atoms.
Answer:
C
Explanation:
It's the amount of products you get compared to all the reactants you use. It's kind of like economy in that it's profit, and the higher the atom economy the more products/profit you have.
Answer:
C.) The measure of how much of the reactants end up as products in a chemical reaction.
Explanation:
I got it right on founders edtell.
Perform the forlowing
mathematical operation, and
report the answer to the correct
number of significant figures.
4568/13 = [?]
Answer:
[tex]\large \boxed{350}[/tex]
Explanation:
In multiplication and division problems, the answer can have no more significant figures than the number with the fewest significant figures.
My calculator gives the result:
[tex]\dfrac{4568}{13} = 351.3846154[/tex]
4658 has four significant figures.
13 has two significant figures.
You must round to two significant figures.
That is, you drop all the digits to the right of the 5 — the red line in Fig. 1 below. You are rounding to the nearest ten.
To round a number to the nearest ten, you look at the number in the ones place (1). See Fig. 2.
If the number to be dropped — the digit in the ones place — is less than 5, you drop the digit in the ones place (Fig. 3). It becomes a zero.
The number in the tens place is a trailing zero. It is not significant.
[tex]\text{The quotient of $\dfrac{4658}{13}$ is $\large \boxed{\mathbf{350}}$}[/tex]
How does antifreeze rely on colligative properties to work?
A. It causes the vapor pressure to increase and the increased outward pressure of the gasoline vapors prevents it from solidifying into ice.
B. It causes freezing point elevation which raises the temperature of the gasoline without letting it freeze.
C. It causes freezing point depression which requires the gasoline to reach a much lower temperature before freezing.
D. It causing boiling point elevation, which raises the temperature of the gasoline without letting it boil so that it can resist the cold.
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It causes freezing point depression which requires the gasoline to reach a much lower temperature before freezing. Hence, option C is correct.
What is the freezing point?Whenever a solute is added to a solution/solvent, it leads to depression in the freezing point of that solution/solvent. Depression in the freezing point of a solution on the addition of a solute is a colligative property.
A colligative property is a physical property which depends upon the number of solutes added not on the nature of solutes which means it does not matter whether we are adding 1000 particles of sugar or salt in water, the depression in the freezing point will occur by the same °C. Also, the more a solute is added the more will be the depression at the freezing point.
The formula for depression at the freezing point is mentioned as under:
Δ T = K x m
where Δ T = freezing point depression;
K = cryoscopic constant;
m = molality of the solution.
For example, The freezing point of water is 0 °C but as soon as we add a 92 gm solute like NaCl (common salt) in 1000 gm of water, its freezing point will be lower to −3.72 °C.
Hence, option C is correct.
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5 (01.01 LC)
Which of the following would be a warning sign that information about a weight loss medication is not reliable science?
Answer:
The scientists and all test subjects involved in the investigation work for the company that sells the medication.
Explanation:
The options are as below:
A. The investigation compared a group that took the medication to a control group that did not take the medication.
B. The scientists and all test subjects involved in the investigation work for the company that sells the medication.
C. The weight loss medication worked for 95 out of the 100 test subjects, while only 15 of the 100 control subjects lost weight.
D. The weight loss results were replicated by scientists conducting a study at an independent institution
The correct option would be that the scientists and all test subjects involved in the investigation work for the company that sells the medication.
When selecting the test subjects for research, the selection must be as random as possible so as to ensure an unbiased outcome and increase the reliability of the research.
Limiting the test subjects to those that work in the company that sells the medication will generally reduce the reliability of the outcome because of element of bias that can be introduced either knowingly or unknowingly.
The test subjects must have been selected from the general population of target users for the medication and not limited to just the employees of the manufacturing company.
Correct option: B
Which of the following is NOT the property of a non-metal? A. Non-rigid structure B. Not ductile C. Low density D. Malleable
Answer:
The answer is D.
Explanation:
Malleable is the property of metal not non-metal.
Answer:
malleable
Explanation:
because a non metal cannot be harmmed into sheetsA substance is followed by the symbol (I) in a chemical Equation. What does the symbol Represent
Answer:
Iodine
Explanation:
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which state of matter is Na OH(s)
Explanation:
SOLID
Sodium hydroxide exists in the solid phase at room temperature. You would find it in the lab as hemispherical white solid pellets. The phase of a substance depends on temperature and pressure. As you heat a solid, it will melt and change to the liquid phase.
how many nitrogen atoms are in 18.8 g of barium nitride
18.8gBa(NO3)2 》》》》gN 》》》》 2.016gN
PLZ HELP! TIMED TEST Which of the following groups of elements are likely to have elements in the three states of matter? (1 point)
Alkali metals
Actinides
Halogens
Lanthanides
Answer:
Halogens
Explanation:
Matter is defined as a substance which has mass and occupies volume. The three states of matter are solid, liquid and gas.
Elements which are present in group 17 are known as halogens.
Elements present in this group are fluorine, chlorine, bromine and iodine.
At room temperature, both fluorine and chlorine exists as a gas.
Bromine exists as a liquid and iodine exists as a solid.
Therefore, we can conclude that halogen groups are likely to have elements in three states of matter.
Consider the hypothetical chemical reaction represented by the equation 3 A + 2 B → A 3B 2 Which of the following is a correct interpretation of this equation? i. 3 grams of A react with 2 grams of B to form 1 gram of A 3B 2 ii. 3 atoms of A react with 2 atoms of B to form 1 molecule of A 3B 2 iii. 3 moles of A react with 2 moles of B to form 1 mole of A 3B 2
Answer:
iii. 3 moles of A react with 2 moles of B to form 1 mole of A 3B 2
Explanation:
A + 2 B → A 3B 2
A chemical equation among other things, gives the stoichiometry of the reaction; that is the relationship between reactants and products.
This relationship is basically stated in moles form the coefficients of the reactants and product.
From the reaction above, we can say;
1 mol of A reacts with 2 mol of B to form 1 mol of A3B2
It cannot be grams because the reactants and products all have different molar masses.
The correct interpretation of the equation of the hypothetical chemical reaction is; Choice (iii) 3 moles of A react with 2 moles of B to form 1 mole of A 3B 2.
Definition:
Chemical equations are equations that make use of chemical formulae and symbols to represent chemical reactions. The left-hand side of a chemical equation represents the reactants and the right-hand side represents the products.
Each reacting entity is also assigned its corresponding stoichiometric coefficient.
However, this stoichiometric coefficient is to quantify the no. of moles of the reactants consumed or products formed as the case may be.
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You are pushing a box with 20 N of force that has
a mass of 10 kg, solve for acceleration
Answer:
Force=mass ×acceleration.
20=10×acceleration.
20=10a.
a=2m/s^2.
Questions
1 Explain why a solid expands when it is heated.
2 Explain how the liquid in a thermometer changes so that it can be used to
measure a temperature.
3 Use particle theory to explain why solids and liquids cannot be compressed
(squashed into a smaller volume).
4 Use particle theory to explain why liquids and gases can flow.
Answer:
answer of question 1 is
Explanation:
solids are denser than liquid and gases because solid particles are closely packed and do not have any empty spaces between their particels so when solid will heated its particles will spread and there will have more spaces between them so a solid expand on heating.
What is the molarity of a 50.0ml aqueous solution containing 10.0 grams of hydrogen peroxide H2O2
Molarity= No of moles of solute * 1000 / vol solution in ml
No of moles= Given mass / Molar mass
Given Mass of solute (H2O2)= 10g
Molar mass of H2O2=34gmol^-1
No of moles= 10/34= 0.294 moles
Volume of solution=50ml
Molarity = 0.294*1000 / 50
Molarity = 5.8M
Define freezing....... Correct and detailed answers will be marked as Brainliest.
The transformation of liquid into solid when it reaches when it's temperature is below freezing point.
Answer:
Freezing:
When liquid is converted to solid, the process is called freezing.
Conditions for freezing:
1) Temperature must be lowered.
2) The temperature should be below 0 degree centigrade.
Example:
The conversion of "liquid water" into "ice".
=> We can use a "freezer" to freeze things.
Which are the physical properties of water
Three determinations were made of the following percentage of oxygen in mercuric oxide. The results were 7.40%, 7.43%, and 7.35%. What was the average percentage?
The melting points of ionic compounds _____
Explanation:
ionic compounds have high melting points
The primary function of a scuba regulator is to: Reduce high-pressure gas in the scuba cylinder to a more breathable intermediate pressure. Reduce high-pressure gas in the scuba cylinder to ambient (surrounding) pressure. Provide a diver with a continuous flow of oxygenated air. None of the above.
Answer:
Reduce high-pressure gas in the scuba cylinder to ambient (surrounding) pressure.
Explanation:
The primary function of a scuba regulator would be to reduce high-pressure gas in the scuba cylinder to ambient pressure.
A scuba regulator is a structure found attached to the scuba cylinder usually carried by scuba divers. The structure regulates the pressure of the breathing gas in the cylinder to a safe level before the gas becomes available for the breathing process of divers.
Usually, the gas in a scuba cylinder is at a high level. Hence, what the regulator does is to bring it down to a level that would be safe for the breathing of the diver.
